NEW DATA: Cruz Leads With Evangelicals, Trump With Independents

Jan Brewer: GOP Convention Rules 'Can Be Changed' for Trump, Too

In his Talking Points Memo, Bill O'Reilly said tonight is a "big night for the Republican Party."

If Donald Trump wins the Wisconsin primary, O'Reilly said, he will likely get the nomination.

If he loses, a much longer nominating process will kick in and Ted Cruz will pick up some steam.

He said that if Trump doesn't get the 1,237 delegates needed, there will be "high noon drama" at the Republican National Convention in Cleveland.

On the Democratic side, O'Reilly said, "that FBI thing" could dash Hillary Clinton's White House hopes, leaving an opening for Bernie Sanders.

"If Hillary is indicted over the email deal, Sanders believes he can win the nomination. So why not hang on?"

O'Reilly closed by saying Trump should explain specifically what he meant with a recent statement that he would stop Mexican citizens in the U.S. from sending money home if the country did not pay for a wall on the border.

"American voters deserve specifics in a very important election, and it looks like the Trump campaign is responding to that."

Watch the full memo above, and discussion with Martha MacCallum about the exit polls below.

How the Back Room Deals Will Get Done at the GOP Convention

'Like a Walking Brita Filter': Will Melania Help Trump With Female Voters?

Trump Reveals How He Would Make Mexico Pay for Border Wall